JPS6231806B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting electromagnet structure used in a superconducting magnetically levitated vehicle or the like.

For superconducting electromagnets, superconducting wires made of special alloys such as Nb and Ti and drawn into multi-core wires are generally used so that the electrical resistance becomes zero when cooled to an extremely low temperature. However, very careful attention is required to maintain the superconducting state of this superconducting wire. In other words, if the superconducting wire is not sufficiently cooled at extremely low temperatures, if it is exposed to a magnetic field higher than expected, or if the superconducting wire is held unstable and moves or vibrates, the superconducting state will be destroyed and it will return to the normal conducting state. The resulting resistance will be combined with the large current that has been flowing until now in a superconducting state, and unless this current is successfully led outside and consumed, the electromagnet will be damaged in an instant due to the heat generated at the bend. There is a danger of doing so. In particular, in the case of superconducting electromagnets used in superconducting magnetic levitation vehicles, the superconducting wire is excited by the strong magnetic field and the vehicle running, and the superconducting wire is bent or moved due to the interaction of the magnetic field and the strong current flowing through the superconducting wire. Therefore, there is a risk that the superconducting state cannot be maintained. However, when superconducting wire is formed into a coil, it is easy to fix it with a winding frame or a coil mold, but there are also lead wires that are pulled out from the coil and connected to external power leads, and permanent wires that open and close the closed loop circuit of the coil. The lead wire from the current switch is difficult to fix and is very prone to problems.

An object of the present invention is to provide a superconducting electromagnet structure in which destruction of the superconducting state is prevented by stably holding a lead wire drawn out from a superconducting coil.

An embodiment of the present invention will be described below with reference to the drawings. First of all, Fig. 1 shows a schematic configuration of a superconducting electromagnet. In the figure, 1 is an inner tank built into an outer tank container (not shown) whose interior is evacuated, and a superconducting coil described later is firmly fixed inside. It is constructed as a hollow truck-shaped container made of stainless steel. A liquid helium tank 2 is arranged above the inner tank 1 and connected to the inner tank 1 by a connecting pipe 3. The inner tank 1 is also provided with a power lead lead-out part 4, through which a power lead 5 is led out from the inner tank 1, and its outer end protrudes outside the vacuum outer tank and is connected to an external power source. The inner tank 1 and power lead 5 are incorporated into the vacuum outer tank via various heat insulating materials and load supporting materials (not shown), and are thermally supported in a vacuum to maintain the extremely low temperature inside. I'm getting better at it. In this state, from the outer end of the power lead 5 to the inner tank 1
The necessary current is passed through the superconducting coil placed inside the
When a persistent current switch (not shown in this diagram) is closed, a persistent current flows in the superconducting coil, and even if the current from the power lead 5 is removed, the persistent current continues to flow in the superconducting coil, forming an extremely powerful magnet. It's becoming like that.

The internal structure of the inner tank 1 in the vicinity of the power lead lead-out portion 4 will be described in detail with reference to FIG. 2. Inside the inner tank 1, a superconducting coil 7 is firmly fixed and held by an insulating flange 8 and a spacer 9. The power lead 5 is composed of a conductor 5A made of copper and a pipe 5B serving as a gas passage for cooling with gas helium. Here, the power lead lead-out portion 4 includes a box body 4A that communicates internally with the inner tank 1, and a power lead penetration portion 4B.
It is constantly filled with liquid helium and kept at an extremely low temperature.

A pipe 5B end of the power lead 5 is welded and fixed to the outer peripheral end of the power lead penetration part 4B,
A pipe 16 is tightly fitted into the center hole by welding, and a connecting fitting part 14 is attached to this via an electrical insulator 15 such as ceramic, and the power lead conductor 5A passes through the center of the pipe 16. It penetrates through the insulator 15 and is electrically insulated from the inner tank 1 and maintained in electrical connection with the connecting fitting part 14 . Here, 11A is a connecting member formed in the shape of a groove from a copper material, etc., and has a member connected to the power lead 5A electrically connected to the connecting fitting part 14 at one end, and a circular shape facing inward of the inner tank 1 at the other end. Insulating materials 12A and 12B are attached to the washer 17 which is welded to the outside of the inner tank 1 and has a structure having a tongue-shaped support part 11B curved in an arc shape.
It is firmly fixed with bolts and nuts 13 through.
In addition, when the connecting member 11A is fixed with the insulating materials 12A, 12B and the bolt/nut 13, the connecting fitting part 14 is made to have some flexibility so that the insulator 15, such as ceramic, is not strained due to dimensional defects. Incorporating a metal bellows (not shown) is also considered an effective means. Here, the superconducting lead wire 10 drawn out from the superconducting coil 7 in the inner tank 1 is attached to the connecting member 11B so as to be attached to the supporting part 11B.
It is led through the 1A groove and fixed by soldering or the like to be electrically connected. Further, a persistent current switch 18 is attached and fixed to the inner corner of the box body 4A of the power lead lead-out section 4 by means of a fixture 20, and the superconducting lead wire 19 from the persistent current switch 18 is connected to the groove of the connecting member 11A in the same manner as described above. The superconducting wire 10 from the superconducting coil 7 is integrally fixed inside the shape by soldering or the like. Although not shown, this persistent current switch 18 is constructed by non-inductively winding a superconducting wire and a heater wire together.
By passing an electric current through the heater wire and heating the superconducting wire, the superconducting wire becomes normal conductive, which produces the same effect as opening a switch. Conversely, when the heater wire is turned off, it is cooled by the surrounding liquid helium and becomes superconducting. This has the same effect as holding the switch and closing the switch.

By doing as described above, the lead wire 10 from the superconducting coil 7 and the persistent current switch 1
The lead wires 19 from 8 are both simultaneously housed in the groove-shaped connecting member 11A and are firmly and stably fixed, and the connecting member 11A prevents the parts of both lead wires 10 and 19 that are loose in the space. In particular, the lead line 10 has a tongue-like support part 1.
1B also reduces the risk that both lead wires 10 and 19 will vibrate and quench even when the vehicle is running.

However, even with the above configuration, the lead line 1
0.19 is a short section, but because there is a loose part in the space, if the vehicle receives strong vibrations for some reason while driving, it will shake a little, making it impossible to maintain the super electric state. There is a risk of inducing quenching. Therefore, in the present invention, the lead wires 10 and 19 are further reinforced and supported.

That is, FIG. 3 is an enlarged perspective view of a portion where the lead wire 10 is drawn out from the superconducting coil 7 and extends to the connecting member 11A, and the superconducting coil 7 is assumed to be molded, and detailed superconducting coil lines are omitted from the illustration. ing. Here, the lead wire 10 drawn out from the superconducting coil 7 passes through the space to the support piece 11.
B, fits in the groove shape of the connecting member 11A and is soldered, but at that time, the lead wire 10
A support conducting wire 21 made of a similar superconducting wire is attached in parallel with this. In addition, one end of the supporting conductor 21 is inserted into the mold of the superconducting coil 7 by cutting off a part of the mold so that it enters an appropriate length along the lead wire 10, and then inserting it into the mold of the superconducting coil 7 to be joined inside the mold. The wire portion and the insulating sheathing are peeled off and soldered to make it possible to conduct electricity, and the other end is housed integrally with the lead wire 10 in the groove of the connecting member 11A and soldered.

By attaching the support conductor 21 in this manner, the lead wire 10 and the support conductor 21 mutually support and reinforce each other and cross the space, and do not shake even when subjected to strong vibrations, which can lead to superconductor breakdown and quenching. There will definitely be no chance of this happening. At the same time, since the supporting conductor 21 is also energized, the allowable amount of energization is doubled in the magnetic field to which they are exposed, together with the lead wire 10, so that even when subjected to the same vibrational excitation, there is no deflection and the wire can be used as a superconducting wire. It has a large capacity, greatly reduces the possibility of normal conductivity due to disturbance, and is extremely resistant to vibration excitation.

In addition, in FIG. 3, the lead wire 10 of the superconducting coil 7 and the reinforcing supporting conductor wire 21 are simply soldered in parallel, but in this case both wires 10, 21
Since the wires are joined together on their narrow sides, the strength cannot be increased very much, and the bending strength cannot be increased to more than twice the width of the wire. However, if both wires 10 and 21 are joined together on their wide surfaces, the thickness will be doubled, and the bending strength will increase in proportion to the cube of the thickness, so it is extremely advantageous in terms of vibration resistance. It is possible that this will happen. Therefore, in this invention, as shown in FIGS. 4 and 5, the lead wire 10A and the support conductor 21 are
The wide surfaces can be joined by shifting the wires A in different steps in the middle, or by twisting the lead wire 10B and the support conductor 21B mutually in the middle as shown in FIGS. 6 and 7. I try to connect like-minded people. This increases reinforcement support strength and provides excellent vibration resistance.

Although not shown, the persistent current switch 18
Similarly to the above, it is also possible to attach a supporting conductor wire to the lead wire 19 from the holder for reinforcement and support.

As described in detail above, this invention connects and holds the lead wire that comes out from the superconducting coil in the inner tank and connects to the external power lead conductor to the connecting member that is fixed to the inner tank in an electrically insulated state, and A support conductor is attached to the connecting part of the wire to reinforce it, so the lead wire does not swing around due to vibration excitation, and this prevents normal conductivity and quenching. At the same time, it becomes an extremely advantageous superconducting electromagnetic structure, as it provides a large margin in the allowable amount of current that corresponds to the strength of the magnetic field.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention.
The figure is a conceptual diagram of the inner tank that is housed in the outer container of a superconducting electromagnet used in magnetic levitation vehicles, etc. Figure 2 is a cross-sectional view of the structure near the power lead lead-out part of the inner tank, and Figure 3 is a superconducting coil. Fig. 4 is a perspective view showing the state of connection between the lead wire and the support conductor, and Fig. 5 a, b, and c show the joining process of both wires in Fig. 4 in order. 6 is a perspective view showing examples of different connection states between the lead wire and the supporting conductor, and FIGS. 7 a, b, and c are 6
FIGS. 3A and 3B are cross-sectional views sequentially showing the joining process of both lines in the figure. FIGS. 1...Superconducting electromagnet inner tank, 2...Liquid helium tank, 3...Connecting pipe, 4...Power lead lead-out part, 4A...Power lead lead-out part box, 4B...
Power lead penetration part, 5...Power lead, 5A
...Power lead conductor, 5B...Power lead tube, 7...Superconducting coil, 8...Insulating flange,
9... Spacer, 10, 10A, 10B... Lead wire, 11A... Groove connection member, 11B... Support part, 12A, 12B... Insulating material, 13... Bolt nut, 14... Connection fitting, 15... ...Insulating material such as ceramic, 16...Pipe, 17...Washer, 18...Persistent current switch, 19...Lead wire, 20...Fixing metal fittings, 21, 21A, 21B...
...Support conductor.

Claims (1)

[Claims] 1. In devices used in superconducting magnetic levitation vehicles, etc., a power lead lead-out part for supplying power to the superconducting coil from the outside is formed in a part of the inner tank storing the superconducting coil, and a power lead lead-out part is formed inside the power lead lead-out part. , a connecting member made of copper or the like is firmly fixed to the inner tank with electrical insulation, and is connected to the power lead conductor which is electrically insulated and conductive to the inner tank, and the inner tank is connected to the inner tank. The lead wire taken out from the superconducting coil in the tank is connected and fixedly supported by soldering or the like, and a supporting conductor is attached to the lead wire by mechanically connecting it from the inside of the coil to the connecting member. Characteristic superconducting electromagnet structure.